Styrenated terpene resin as well as methods of making and using the same

Abstract

The present invention relates to styrenated terpene resin, as well as methods of making an using the same.

Description

RELATED APPLICATION DATA[0001]This application claims priority of U.S. Provisional Patent Application Ser. No. 60 / 831,422, filed Jul. 17, 2006, which application is hereby incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to polymers, to products comprising such polymers, and the methods of making and using such polymers and products. In another aspect, the present invention relates to styrenated terpene resin, to products comprising such resin, as well as to methods of making and using such resin and products.[0004]2. Description of the Related Art[0005]Modified terpene resins, such as styrenated terpene resins find use as tackifiers in the adhesive industry, especially the are of hot melt packaging, non-woven, and hot melt pressure-sensitive adhesives. Such resins are co-polymers of a terpene—obtained from pine trees (via sulfate turpentine, a by-product of the Kraft paper manufacturing process or gum turpentine...

AI Technical Summary

Benefits of technology

"The present invention provides a synthetic route to styrenated terpene resins with high yields and minimal or no limonene. This is achieved by using high levels of CST-derived terpenes such as beta pinene and alpha pinene, and a Lewis acid catalyst system that is not based on toxic or expensive systems. The resulting styrenated terpene resin has acceptable characteristics to function comparably to commercialized limonene-based styrenated terpene resins. The invention also provides an adhesive comprising the styrenated terpene resin and a method of adhering surfaces using the adhesive."

Problems solved by technology

In contrast, free radical or anionic polymerization of styrene and a terpene tends to produce resins with substantially higher MW (e.g. U.S. Pat. No. 5,364,723 mentions syntheses of styrene-myrcene resins with Mw values of greater than 38000 and Mn values greater than 8000 obtained via free radical and anionic polymerization processes), and such resins cannot adequately function as tackifiers in hot melt packaging, non-woven adhesives, or hot melt pressure-sensitive adhesives.

When syntheses of styrenated terpene resins are carried out using other terpenes (i.e. alpha pinene, beta pinene, delta-3-carene, etc.) under Lewis acid-catalyzed cationic polymerization conditions, one is confronted with one or more of the following hurdles: difficulty to build up MW and softening point, severe yield loss, excessive MW build-up and therefore an unfavorable impact on resin compatibility in adhesive systems, a strong tendency toward excessive formation of low MW by-products, etc.

The crude limonene is not pure enough to allow its use as a monomer for cationic polymerization processes, and consequently, resin producers refine the crude.

If the volumes of limonene-based polyterpenes for these new uses do grow rapidly, then the availability of styrenated terpene resins for applications in traditional areas would be jeopardized.

However, cationic polymerization of alpha pinene to produce high softening point and high MW resins is not straightforward under standard conditions of Lewis Acid-catalyzed polymerizations.

Standard processes with alpha pinene as the key / sole terpene monomer lead to low yields of solid resin and even at these low yields, the softening points are not very high.

However, none of these patents describes the co-polymerization of alpha pinene with a vinylaromatic, such as styrene or alp ha methylstyrene.

A major drawback about the US patents listed above is that they all involve the use of toxic and sometimes very expensive catalyst systems such as antimony halides, trialkylhalosilanes and organogermanium halides and alkoxides.

Catalyst removal and / or recovery systems with such processes can also be a hurdle for economic justification for employing such polymerization conditions.